The butterfly emerges in about ten to fourteen days, according to temperature. The male is violet-blue with the veins rather darker; the outer margin is narrowly bordered with blackish, and there are some black dots on the outer margin of the hind wings; the fringes are white, and there is a slender tail on the hind wings. The female is brownish, tinged with violet towards the base; the hind wings have black spots on the outer margin, and some of these are inwardly edged with orange; the tails are slightly longer than those of the male. All the available information concerning the occurrence of this species in England has already been given. No doubt the localities from which specimens were recorded have been closely investigated during the past twenty years, but no further captures of this butterfly have been recorded. This seems to indicate that it is not really indigenous, but that its presence here may possibly have been due to accidental introduction. The spring form, _polysperchon_, is smaller than the specimens occurring in the summer, but so far that form has not been seen in England. The species is widely distributed over Central and Southern Europe, and its range extends through Northern Asia to Amurland, Corea, and Japan. It is also represented in Northern and Central America by var. _comyntas_, and has been recorded from Australia. The Silver-studded Blue (_Lycæna argus_ = _ægon_). The male of this butterfly (Plate 105) is purplish-blue with a black border on the outer margins, and sometimes black dots on that of the hind wings. The female is sooty-brown, powdered to a greater or lesser extent with blue scales on the basal area; there is generally a series of orange marks forming a more or less complete band on the outer margin of the hind wings, and sometimes on the fore wings also. The under side is bluish-grey in the male, and brownish-grey in the female; the black spots are ringed with white, and on the fore wings there is one at the end of the discal cell and a series of seven beyond; the hind wings have from three to five spots before the discal spot, and a curved series of seven beyond; there is a black-edged orange band on all the wings, and beyond this on the hind wings there is a series of metallic blue centred spots; hence the English name of the butterfly, given to it by Moses Harris, which is certainly more suitable than Petiver's "Lead Argus."